细菌代谢产物中小分子有机酸的高效毛细管电泳分析

Detection of the organic acids in bacterial metabolites by high-performance capillary electrophoresis

目的建立高效毛细管电泳法测定甲酸、乙酸、丙酸、丁酸、乳酸的分析方法，测定细菌代谢产物中的小分子有机酸。方法采用毛细管：Beckman coulter未涂层50μm×60cm（有效长度50cm）；缓冲溶液：pH10．5的10mmol／L（含0．5mmol／LCTAB）的硼砂溶液；检测波长214nm，分离电压-20kV，进样压力为1．0psi，进样时间为10s。结果4min内甲酸、乙酸、丙酸、丁酸、乳酸得到基线分离。线性范围分别为：甲酸3．8～30．7mg／L（r=0．9971）；乙酸3．3～52．5mg／L（r=0．9961）；丙酸3．1～49．5mg／L（r=0．9993）；丁酸3～48mg／L（r=0．9925）；乳酸7．5～60．5mg／L（r=0．9995）。平均回收率分别为：甲酸99．29％（RSD=0．67％）；乙酸98．90％（RSD=1．36％）；丙酸99．65％（RSD=0．65％）；丁酸99．35％（RSD=0．42％）；乳酸98．06％（RSD=1．44％）。结论该方法简单、快速、准确，可用于细菌发酵液中代谢产物有机酸的检测。

Objective To establish a method for determining formic acid, acetic acid, propionic acid, butyric acid and lactic acid in bacterial metabolites by the high-performance capillary electrophoresis. Methods Samples were analyzed on a Beckman Coulter （50 μm × 50 cm） uncoated fused-silica capillary using 10 mmol/L borate buffer （ pH 10.5 ,containing 0.5 mmol/L CTAB）. The UV detection wavelength was 214 nm,the separation voltage - 20 kV and injection pressure 1.0 psi × 10 s. Results Standard samples of formic acid,acetic acid,propionic acid,butyric acid and lactic acid were separated well in 4 minutes, and their linear ranges were 3.8 - 30.7 mg/L （ r = 0. 997 1 ）, 3.3 - 52.5 mg/L （ r = 0. 996 1 ）, 3.1 - 49.5 mg/L （ r = 0. 999 3 ）,3.0 - 48.0 mg/L（ r = 0.992 5 ） ,7.5 - 60.5 mg/L （ r = 0. 999 5 ）, respectively, their average recoveries were 99.29% ,98.90% ,99.65% ,99.35% and 98.06% , respectively. The RSD values （n = 6） of formic acid, acetic acid, propionie acid, butyric acid and lactic acid were 0.67% , 1. 36% , 0. 65% ,0. 42%, 1.44% ,respectively. Conclusion The method is simple ,rapid and accurate for detecting the organic acids in bacterial metabolites in fermentation liquor.